https://bugs.freedesktop.org/show_bug.cgi?id=107213
--- Comment #22 from Shmerl shtetldik@gmail.com --- It looks like it's related to https://bugs.freedesktop.org/show_bug.cgi?id=107978
My monitor (Dell U2413) has a setting for toggling DisplayPort 1.2. When I disable it, Wayland Plasma session isn't crashing anymore and is logging in properly! So it's likely an amdgpu issue actually.